QoS for Long-Range Wireless Sensors Under Duty-Cycle Regulations with Shared Activity Time Usage

Long-range radio can connect sensors/IoT devices without complex and costly deployment of relay nodes. However, this flexibility comes with stricter legal regulations such as maximum radio activity time per 1-hour period. Under such constraints it is difficult to provide service guarantees, which is quite paradoxical when devices are deployed for surveillance systems. The approach we propose allows devices to go “exceptionally” beyond the activity time limitation by borrowing time from other devices. The mechanism is not intended to be used on a regular basis, where a device is commissioned to always report data at a rate that makes it consuming more than the allowed duty-cycle limitation, but to offer a “last chance” solution for providing better surveillance service guarantees while globally satisfying duty-cycle regulations. The proposition has been implemented on our long-range image sensor platform, and preliminary experiments show that it can maintain the system’s consistency and keep the number of control messages small while being capable of handling sleep-wakeup behavior and dynamic insertion of new devices. Although initially targeted for image sensors, the proposition can also be deployed to increase the quality of service of traditional sensors by guaranteeing that important messages can be sent despite the duty-cycle regulation limit.